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(WASHINGTON) -- An independent FDA advisory panel on Thursday and Friday is set to discuss and vote on whether to authorize Moderna and Johnson & Johnson Covid-19 vaccine boosters for those 18 and older.

The outside experts will also consider new data from the National Institutes of Health on the potential benefits of mixing and matching vaccines for booster shots.

Early results from the highly anticipated NIH study finds that boosting with a shot different from what people got the first time appears to be safe and effective.

The non-peer reviewed study evaluated all three vaccines -- Pfizer, Moderna and J&J -- finding that no matter the booster, all study participants saw a "substantial" uptick in antibody levels after a booster shot.

Though promising, more research is likely needed on mixing and matching. For now, the FDA and CDC are slated to weigh in on whether to authorize additional booster doses of Moderna and Johnson & Johnson shots for those who received the same original vaccine.

This week's meetings are the first step in a long process: The FDA itself and the Centers for Disease Control and Prevention would both need to sign off on the panel's recommendations about who should get boosters and when -- and the earliest that could happen is the following Friday, Oct. 22.

On Thursday, the panel will discuss and vote on a potential Moderna booster, and hear presentations from both the company and FDA representatives; Israel's director of public health health will give a presentation about the results of Pfizer booster shots in that country.

The FDA panel will ask questions and debate the benefits versus risks of a Moderna booster and an initial, non-binding vote on the Moderna booster has been scheduled for Thursday afternoon.

On Friday, the panel will discuss and vote on a Johnson & Johnson booster, in addition to hearing NIH's presentation on mix and match booster data.

Johnson & Johnson’s posted a summary of its research Wednesday, making the argument for a second shot, same dose, roughly six months after the single-shot vaccine.

An initial, non-binding vote on the Johnson & Johnson booster has been scheduled for Friday afternoon.

Once the FDA advisory panel votes on recommendations for each booster, the FDA itself needs to formally amend the current emergency authorization. FDA career scientists are expected to authorize boosters for Johnson & Johnson and Moderna within days of the independent panel's non-binding vote.

Then, the question goes to CDC’s independent advisory panel of experts. That panel has scheduled a meeting for next Wednesday Oct. 20 and Thursday Oct. 21 to discuss boosters for Moderna and Johnson & Johnson. Those outside experts will weigh in with their recommendations, which are also non-binding.

Once that happens, CDC Director Rochelle Walensky must sign off, which typically happens within 24 hours of the panel's recommendations.

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